George Monbiot is right to point out the need for those involved in the 26 March rally to have an idea of what it is they're fighting for as well as what it is they're protesting against. As he says:

"The lesson to be drawn from previous battles is that lasting change does not happen until we unite behind what we want – not just against what we do not. Without clear aims we remain trapped by our opponents, responding to their agenda rather than forcing them to respond to ours."

However, Monbiot does people a disservice if he assumes that those of us gearing up to take part in the biggest protest this country has seen since the February 2003 march against the Iraq war haven't already thought these issues through; or that we see 26 March as nothing more than an end in itself and have no clearer agenda beyond protesting on the day and voicing our opposition to the government's swingeing cuts.

I'm going to be in London on 26 March not simply because I'm against just about everything the Eton boys that run this place represent or because I want to take a stand against what they're trying to do to this country, but also because I do know what it is I'm fighting for. And that's nothing more or less than this country's future: the future of the welfare state, of our public services, of the education system, of pensions and of the NHS. I'm fighting for my future and my children's, and the future of anyone else who wasn't born with a silver spoon in their mouth: all of those who are set to lose so much if the government continues on its destructive course.

I'm marching because I support nurses, teachers, care assistants, Sure Start centres and libraries. For the voluntary and community sector, for hospitals, midwives and schools. I'm marching because I believe that the state has a responsibility to take care of all of its citizens – not just those who can afford to pay but everyone, no matter who they are or what they've done. I'm marching because I'm for universal benefits from the cradle to the grave, and because I believe that disabled people, the young and the elderly have just as much right as everyone else to live lives free from poverty and stigma.

I'm marching because I believe that in a civilised society, in a 21st century society, there can be no justification for allowing people to simply fall through the cracks, unnoticed, uncared for and alone; I believe that people must always come before profit and that government should be for the people, and not just for its wealthy and privileged friends. I'm marching because I am for all of these things and more, and because I know that if the Tory-led coalition's cuts go through, it is the poor and the vulnerable who are set to suffer the most.

I'm marching because I cannot in all conscience not march; because I have to; because I know what it is I'm against and because – contrary to Monbiot's assumption – I also know precisely what it is I'm for.

I would urge anyone else who can make it to London on 26 March to join me and the hundreds of thousands of others who will be protesting on that day; the day the "big society" will be taking to the streets.